Vaginal discharge caused by secretions from the vagina may occur throughout the menstrual cycle. Such discharge may result from both non-infectious causes and infectious causes. The non-infectious causes include physiological causes, such as puberty, menstrual cycle, sexual activity, pregnancy and menopause, as well as non-physiological causes such as the presence of a foreign body, chemical, drug, and gynecologic abnormalities. The infectious causes producing vaginal secretions include Candida albicans, Trichimonas vaginalis, and Bacterial vaginosis (BV).
Normal healthy vaginal tissue is populated by protective vaginal bacterial flora, such as hydrogen peroxide-producing lactobacilli. BV is an infection involving an imbalance in the vaginal bacterial flora. In this condition, the lactobacilli and other normal flora are replaced with pathogenic anaerobic coccobacilli. Studies associate BV with some serious conditions affecting the female reproductive system, encompassing complications of pregnancy, childbirth and fertility. These include pre-term birth, low birth weight infants, premature rupture of the membranes, chorionic and amnionic infection, infertility, ectopic pregnancy, and other perinatal/reproductive tract complications.
BV is one of the commonest causes of abnormal vaginal discharge. The condition is under diagnosed partly because of the lack of an easy and acceptable method of diagnosis. Genito-urinary medical physicians make the diagnosis of BV by various means including examining stained preparations of vaginal discharge under the microscope and relating this to the patient's symptoms. This is rarely performed by general practitioners, family planning doctors, gynecologists and other health care workers because of the lack of time and expertise.
An early study of BV involved comparisons of the pH of vaginal fluids of women known to be suffering from BV with those known to be free of the disease (Gardner et al., 1955, Am. J. Obstet. Gynecol. 69:962). All of the BV positive women in the study were determined to have a vaginal fluid pH greater than 4.5, and 91% of these women had a vaginal fluid pH greater than 5.0. Of the normal (disease-free) women in the test, 92% were found to have vaginal pH between 4.0 and 4.7. The conclusion drawn from the study was that a vaginal pH equal to or greater than 4.7 in conjunctions with other clinical criteria was indicative of the presence of BV.
BV can be diagnosed by external examinations of vaginal secretions, U.S. Pat. No. 4,532,216 discloses the use of quaternary ammonium polyelectrolyte salts in a test means, test device, and method for determining the ionic strength or specific gravity of a test sample as well as a method for making the device. U.S. Pat. No. 6,099,801 discloses a test device for detecting salts of volatile amines in aqueous fluids, useful in the diagnosis of bacterial vaginosis in vaginal secretions. U.S. Pat. Nos. 5,660,790 and 5,910,447 disclose a test device and a method for analyzing the pH of an aqueous liquid sample.
U.S. Pat. No. 5,897,834 discloses a device useful for the differentiation between urine and vaginal secretions associated with vaginosis or urine and amniotic fluid. The device includes the use of indicators with a negatively charged group immobilized to a solid polymer substrate containing quaternary ammonium groups. Further the device includes a gaseous amine-releasing reagent and an amine indicator. The use of the polymer substrate containing quaternary ammonium groups is disclosed to have an advantage of sharpening the pH dependent color transition. However, these test devices are not applicable for intravaginal examination.
BV can be also diagnosed by intravaginal secretion sampling. WO95/03423 discloses an amine tester for diagnosing bacterial vaginosis and vaginitis comprising at least one receptacle containing an alkaline medium; a test swab; and at least one control assembly for producing as a control smell volatilized amines, said test swab being, in use, contaminated with a sample from a vaginal discharge whereby a comparison of the smells resulting from the exposure of the test swab to the alkaline medium and from the control assembly enables the detection of volatilized amines from the test swabs.
U.S. Pat. No. 5,217,444 discloses a tampon for absorbing vaginal discharge, characterized in that the tampon includes two pH indicator materials of different pH values indicating by a color change the acidity or alkalinity of a liquid coming into contact with said materials, said pH indicator materials being included in the tampon so as to be wetted by the secretions absorbed by the tampon, thereby providing an indication of the health condition of the person's body. The specific compositions of the chemical means however are not defined.
U.S. Pat. Nos. 6,627,394 (the '394 patent) and 6,921,647 (the '647 patent) a continuation-in-part of the '394 patent, of the applicant of the present invention disclose a secretion-monitoring article for identifying a secreted biological fluid having a body with an absorbent material and least one pH determining member and a reagent associated with the absorbent material. The article is capable of indicating the presence of amniotic fluid, or secretions associated with bacterial, parasite, fungal, or yeast infections without giving a false positive result upon exposure to urine. However, the disclosed article may include unacceptable levels of cytotoxic components and thus is not suitable for use in intravaginal articles, such as a swab.
There is an unmet need for a non-toxic composition that can provide intravaginal monitoring of vaginal infections such as bacterial vaginosis.